Using common interest formulae:

In 1945 the UK took a loan of $4,336,000,000 at a fixed annual rate of interest of 2% to be repaid in 50 annual installments.

As a simple "mortgage" the annual payment would have been $90,455,700.23.

The total paid back at the end of the 50 years would have been 4,522,705,012.

The total interest paid would have been $186,705,012.

Payments were formally suspended during at least one 6 year period to assist the UK with some "internal troubles." Because the UK "skipped a few payments" the total paid in interest may have been slightly more than was originally expected; but no forclosure actions were filed.

John